Diabetes in pregnancy among Sri Lankan women: gestational or pre-gestational?

Introduction: There is an exponential rise in the occurrence of diabetes during pregnancy in South Asia. However data is sparse on the actual pre-gestational diabetes mellitus (PGDM) versus gestational diabetes mellitus (GDM) case-mix. The applicability of the WHO gold standard diagnostic tool – 75g oral glucose tolerance test (OGTT) – and its optimal timing between 24-28 weeks gestation in South Asians is unknown.

Objective: To assess optimal timing for diagnosis, determine the case-mix of PGDM and GDM and their specific risk profiles, insulin needs and pregnancy outcomes among Sri Lankans.

Method: Prospective data was collected from consecutive women diagnosed with diabetes in pregnancy, at the Professorial Unit, De Soysa Hospital, Colombo from 1st January 2010, - 28th Feb 2011. All were screened by an initial 2 hour post prandial (PPBS) at antenatal booking and risk stratified to determine the optimal timing of OGTT.

Results: (Total n=140) GDM and PGDM occurred in 82% and 18% of patients respectively.

GDM (n=115) Mean age 32.16±5.26; booking POA 13.7±5.8weeks; booking BMI 26±4.9kg/m2. Risk factor profile – 1(33%); 2(29.3%); 3 (29%); 64% were detected before 24 weeks. Those >30 years were 67% among early diagnosis versus. 36% among those diagnosed between 24-28 weeks (p=0.02). Previous miscarriages were 36% among early diagnosed versus. 18% among those diagnosed late (p=0.145). Pregnancy induced hypertension occurred in 7.8% with similar occurrence in both subgroups.

Pregnancy outcome was similar in the two subgroups (100% live births, mean birth weight 3.127±0.50kg, macrosomia 21%; LSCS 43%, pre-term 6.9%; neonatal hypoglycaemia and jaundice 11%; congenital malformation=1(0.9%).

Pre-GDM (n=25) Mean age 32.92±5.9 (2/3 >30 years); booking POA 12.7±6.1weeks; booking BMI 23.49±3.52kg/m2, significantly less than GDM group (p=0.03). Risk factor profile – 1(28%); 2(28%); 3 (32%). Previous miscarriage had occurred in 24% with more still births than in GDM group (p=0.002). Previous GDM was significantly more (p=0.03). Pregnancy induced hypertension occurred in 8%.

Pregnancy outcome: 100% live births. Mean birth weight 3.014±0.56kg; macrosomia 20%; LSCS 44%; pre-term 16%; neonatal jaundice and hypoglycaemia 20% (significantly more than GDM group, p=0.02); congenital malformation =1(4%).

Conclusion: Unequivocal PGDM occurs among 18% of pregnant diabetics, among older multiparous women with previous GDM and still births. GDM was diagnosed before the internationally recommended 24 weeks in 64%, although their insulin requirement was significantly less than those diagnosed after 24 weeks.

Recommendations: 1) The current timing in pregnancy for screening by OGTT in Sri Lanka requires review. 2) A comprehensive pre-conception screening programme, particularly for older women with previous GDM and/or previous pregnancy loss, is required.

DOI: http://dx.doi.org/10.4038/sjdem.v1i1.4181

Sri Lanka Journal of Diabetes Endocrinology and Metabolism 2011; 1: 8-13